Titanium alloy



United States Patent 9 TITANIUM ALLOY Robert I; Jaltee, Worthington, and Horace R. Ogden and Daniel J. Maykuth, Columbus, Ohio, assignors, by mesne assignments, to Rem-Cru Titanium, Inc., Midland, Pa., a corporation of Pennsylvania No Drawing. Application August 19, 1952, Serial No. 305,284

11 Claims. (Cl. 75-175.5)

This invention relates to titanium-base alloys, and more specifically to quaternary and higher components, titanium-base alloys, containing as essential constituents, aluminum and iron together with one or more of the metals manganese, molybdenum and chromium.

A broad range of analysis of alloys in accordance with the invention will contain from about 1 to 7.5% aluminum, about 1 to iron, and about 1 to 20% in aggregate of metal of the group manganese, molybdenum and chromium, wherein the chromium may range up to about 12%, molybdenum up to about 8% and manganese up to about 6%.

As shown by the test results presented below, the majority of the analyses within the aforesaid range, are sufficiently ductile to be rolled, forged or otherwise Wrought or fabricated. The relatively few analyses which are too brittle for such purposes, are useful in cast form.

A preferred range of analysis for assuring adequate ductility for purposes aforesaid, together With high strength is that containing about 3 to 7.5% aluminum, about 1 to 5% iron and about 1 to 3% of metal of the group manganese, molybdenum and chromium.

In the alloys of the invention, the presence of some carbon is desirable, for further enhancing the tensile properties, consistent with retention of adequate ductility, but the carbon should not exceed about 0.3%, about 0.25% carbon being the preferred upper limit.

In Patent No. 2,575,962, granted November 20, 1951, the present inventors have disclosed a group of ternary alloys of titanium, aluminum and iron, optionally containing carbon up to about 0.25 The present invention contemplates additions to the ternary alloys of the aforesaid patent, of one or more of the metals manganese, molybdenum and chromium. The alloys of the present invention are an improvement over the ternary alloys of the aforesaid patent in several respects. The beta phase in these alloys is less subject to transformation to alpha or eutectoid decomposition than is the beta phase in the ternary alloys of the above-mentioned patent. Moreover, the presence of one or more of manganese, molybdenum and chromium, along with iron, permits the use as alloying constituents of the commercial complexes known as ferro-chrome, term-manganese and ferro-molybdenum.

In the alloys of the invention, containing either or both chromium and molybdenum, manganese may be substi tuted in whole or in part for iron. Such alloys may contain, in addition to about 1 to 7.5% aluminum, about 1 to 16% of metal of the group chromium and molybdenum and about 1 to 6% of metal of the group iron and manganese.

Typical alloys in accordance with the invention, together with their mechanical properties are set forth in the following Table I:

Table I.-' liAZ-Fe base alloys with additions of 01, Mo and Mn ANNEALED CONDITION Composition Percent (Balance Gross- Ultimate Titanium) Section Strength HVierers Bend '1 (1,000 at ness s. i. Al Cr Mo Fe Mn 0 p 5 1. 25 1. 25 310 1. 2 131 5 1. 25 1.25 0 25 346 1. 5 150 5 1. 25 1.25 331 1. 4 126 5 1 25 1.25 0.25 346 1.5 153 5 2.5 2. 5 334 1.1 131 5 2. 5 2.5 0 25 376 1. 2 148 5 8 8 1 322 0 -145 5 8 8 2 352 0. 9 1 146160 5 8 8 2 328 0 130-145 5 8 8 4 342 0 1 135-155 5 6 6 1 2 l 340 0.8 1 135-155 5 6 6 2 4 353 Brittle 1 -160 5 8 8 1 2 346 0. 4 1 140-155 5 8 8 1. 5 3 l. 359 1. 7 1 -160 5 8 8 2 4 412 Brittle 1 165-185 5 9 3 1 2 338 0. 4 1 135-150 5 9 3 2 4 362 5. 4 1 145-165 5 9 3 3 6 395 Brittle 1 160-175 5 l2 4 l 2 356 1. 7 1 140-160 5 12 4 2 4 392 Brittle 1 -175 5 l0 1 2 321 1.8 130-145 1 Tensile strength values converted from cross-section Vickers hardness values by multiplying by a factor of 400 to 450. Thus 200 Vickers X 400 to 450 equals a tensile strength from 80,000 to 00,000 p. s. i.

ployed may be that of commercial purity, as produced, for

example, by the magnesium reduction of titanium tetrachloride, or by other methods, or the iodide base material may be used.

By way of comparing the mechanical properties of the quaternary and higher component alloys of the present invention, with the ternary alloys of the aforesaid patent, a ternary alloy containing 5% aluminum and 1% iron, has, in the fully annealed condition, an ultimate strength of 97,500 p. s. i., a surface hardness of 306 Vickers and an elongation of 17% As shown by the data in the above table, the addition to this alloy of 8% chromium and 8% molybdenum, in accordance with the present invention, increases the ultimate strength to 130,000 to 145,000 p. s. i., the hardness to 322 Vickers, the bend ductility being zero, thus to produce an alloy with greatly increased strength and ductility as compared to the ternary alloy aforesaid. Also as shown by the above table, the further addition of 2% manganese to the 5Al--1Fe-8Cr-8Mo alloy aforesaid, increases the ultimate strength to 140,000 to 155,000 p. s. i., the hardness to 346 Vickers, and the bend ductility to 0.4. Thus the strength is further increased with no substantial reduction in ductility. It will be seen, therefore, that the alloys of the present invention constitute a pronounced improvement over those of said patent.

In the test results of the foregoing table, the alloys were tested in the annealed condition. .For the alloys with the combined contents of iron, chromium, manganese and molybdenum of 10% or less, the annealed condition was obtained by annealing 3% hours at 850 C. and slow cooling to room temperature. For the alloys with a combined content of iron, chromium, manganese and molybdenum totalling more than 10%, the annealed condition was obtained by heating the alloys into the beta field at 900 C. and cooling rapidly therefrom. The alloys with a total of 10% or less combined beta-promoting elements are microstructurally mixed alpha-beta titaniumbase alloys, consisting predominantly of equiaxed grains of alpha titanium with beta titanium present as a grain than 10% combined beta-promoting elements are predominantly beta phase in structure. When carbon is present, and increases in amount, increasing amounts of titanium carbide appear. These alloys may be further strengthened by cold Working or by aging them after a high-temperature solution anneal. They may be rendered stable by annealing them at a suificiently low temperature to effect transformation of the unstable beta phase to alpha, leaving a structure of alpha and stable beta phases. The stability of these alloys so treated is such as to make them valuable for use as structural parts which in service are exposed to elevated temperatures, as from 300-5 00 C., such, for example, as components of high speed aircraft and their power plants.

This application is a continuation-in-part of our abandoned co-pending applications Serial No. 187,369, filed September 28, 1950, and Serial Nos. 255,545 and 255,546, both filed November 8, 1951.

What is claimed is:

1. An alloy containing: about 17.5% aluminum, about 1-5% iron, a metal selected from the group consisting of manganese, molybdenum and chromium in the ranges 16%, 18% and 1-12% respectively, up to 0.3% carbon, and the balance titanium.

2. An alloy containing: about l7.5% aluminum, iron and manganese from about 1% to 6% in aggregate, about ll6% of metal selected from the group consisting of chromium and molybdenum, and the balance substantially all titanium.

3. An alloy containing: about 1-7.5% aluminum, about 1-5% iron, about 112% chromium, up to 0.3% carbon, and the balance substantially titanium.

4. An alloy containing: about 17.5% aluminum, about 4 1-5% iron, about 1-8% molybdenum, up to 0.3% carbon, and the balance substantially titanium.

5. An alloy containing: about 1-7.5% aluminum, about 15% iron, about 16% manganese, up to 0.3% carbon, and the balance substantially titanium.

6. An alloy consisting essentially of: 3-7.5% aluminum, 15% iron, 1-3% chromium, up to 0.3% carbon, balance titanium.

7. An alloy consisting essentially of: 37.5% aluminum, 15% iron, 1-3% manganese, up to 0.3% carbon, balance titanium.

8. An alloy consisting essentially of: 37.5% aluminum, 1-5% iron, 13% molybdenum, up to 0.3% carbon, balance titanium.

9. An alloy consisting essentially of about 1%7.5% aluminum, about 6%12%- chromium, about 3%8% molybdenum, about 1%6% of metal selected from the group consisting of iron and manganese, and the balance titanium.

10. An alloy containing about 1%7.5% aluminum, about 1%5% iron, about 1%6'% manganese, a metal selected from the groupmolybdenum and chromium in the ranges 1%8% and 1%-12% respectively, the aggregate of manganese and saidmetal not exceeding about 20%, up to about 03% carbon, and the balance substantially titanium.

11. An alloy consisting essentially of about; 1 to 7.5% aluminum, 1 to 5% iron, 1 to- 20% of at least one element selected from the group consisting of manganese, molybdenum and chromium, but not to exceed about 6% of manganese, 8% of molybdenum and 12% of chromium up to 0.3% carbon, and the balance substantially titanium.

' No references cited. 

1. AN ALLOY CONTAINING: ABOUT 1-7.5% ALUMINUM, ABOUT 1-5% IRON, A METAL SELECTED FROM THE GROUP CONSISTING OF MANGANESE, MOLYBDENUM AND CHROMIUM IN THE RANGES 1-6% 1-8% AND 1-12% RESPECTIVELY, UP TO 0.3% CARBON AND THE BALANCE TITANIUM. 